Honda civic 2008 - malfunction Light

[vkesava1]

Hello there,

I was driving yesterday, suddenly malfunction light came on. A friend of mine, ran diagnostics and found the code p0128. coolant thermostat (coolant temperature below regulating temperature how do I fix this ??

please help. Thanks

[ShermanEF9]

its probably due to the cold weather. its expecting a certain temp range before a certain period of time is up. my dads car did this when it got cold as well. you can try the old cardboard infront of the rad trick.

[Iqoair]

Probably the thermostat opening too early / weak. Would need to do temperature checks on the hoses to confirm. Most likely the thermostat.

[vkesava1]

Originally posted by Iqoair
Probably the thermostat opening too early / weak. Would need to do temperature checks on the hoses to confirm. Most likely the thermostat.

Could you please let me know, how to do the temperature checks on the hoses? How much it would cost at the dealer ?